Heme/Onc - First Aid Flashcards
Erythrocyte Features
-carries O2 to tissues and CO2 to lungs -anucleate, biconcave -large surface area to volume ratio for rapid gas exchange -life span = 120 days -uses glucose for energy
The membrane of erythrocytes contains…
chloride-HCO3- antiporter which allows RBCs to export HCO3- and transport CO2 from the periphery to the lungs for excretion.
A reticulocyte is…
an immature erythrocyte; a marker of erythroid proliferation.
Anisocytosis
varying size
Poikilocytosis
varying shape
Platelet (thrombocyte) features
-invovled in primary hemostasis -small cytoplasmic fragment derived from megakaryocytes -life span = 8-10 days
When a platelet is activated by endothelial injury, it will…
aggregate with other platelets and interact with fibrinogen to form a platelet plug.
Platelets contain…
dens granules (ADP and calcium) and alpha granules (vWF and fibrinogen).
Thrombocytopenia or decreased platelet function results in…
petechiae.
vWF receptor
GPIb
Fibrinogen receptor
GPIIb/IIIa
Leukocytes are divided into…
granulocytes (neutrophils, eosinophils, basophils) and mononuclear cells (monocytes and lymphocytes).
Normal Leukocyte level
4000-10000
WBC differential from highest to lowest
Neutrophils Like Making Everything Better Neutrophils (54-62%) Lymphocytes (25-33%) Monocytes (3-7%) Eosinophils (1-3%) Basophils (0-.75%)
Neutrophils are…
an acute inflammatory response cell seen in bacterial infections. -phagocytic -multilobed
Small neutrophils with more numerous specific granules contain…
ALP, collagenase, lysozyme and lactoferrin.
Larger neutrophils with less numerous azurophilic granules contain…
proteinases, acid phophatase, myeloperoxidase and beta-glucoronidase.
Hypersegmented PMNs (5 or more lobes) are seen in…
vitamin B12/folate deficiency.
Increased band cells (immature neutrophils) reflect states of…
myeloid proliferation (bacterial infections, CML).
Monocytes differentiate into…
macrophages in tissues.
Monocyte features
-large, kidney-shpaed nucleus -“frosted glass” cytoplasm
Macrophages act to…
phagocytose bacteria, cellular debris and senescent RBCs and scavenge damaged cells and tissue.
Macrophages are activated from monocytes via…
gamma-interferon.
Macrophages can function as…
antigen presenting cells via MHC II.
Surface marker for macrophages
CD14
Macrophages are an important component of…
granuloma formation.
Eosinophils defend against…
helminthic infections (w/ major basic protein).
Eosinophils features
-bilobate nucleus -packed with large eosinophilic granules -highly phagocytic for Ag-Ab complexes
Eosinophils produce..
histaminase and arylsulfatase (these help limit rxn following mast cell degranulation).
Causes of eosinophilia
NAACP N: neoplasia A: asthma A: allergies C: CT disorders P: parasites
Basophils mediate…
allergic rxns.
Basophil features
densely basophilic granules containing heparin (anticoagulant), histamine (vasodilator) and leukotrienes.
Isolated basophilia is rare but can be a sign of…
myeloproliferative disease (particularly CML).
Mast cells mediate…
allergic rxn in local tissue. (resemble basophils)
Mast cells can bind…
the Fc portion of IgE to the membrane. IgE cross-links upon Ag binding, causing degranulation, which releases heparin, histamine, and eosinophilic chemotactic factors.
Mast cells are involved in…
type I HSR.
Mast cell degranulation is prevented by…
cromolyn sodium (used for asthma prophylaxis).
Dendritic cells are…
highly phagocytic APCs that function as the link between the innate and adaptive immune systems.
Dendritic cells express…
MHC class II and Fc receptors on the surface.
Dendritic cells of the skin are called…
Langerhans cells.
Lymphocyte appearance
round, densely staining nucleus with a small amount of pale cytoplasm
B lymphocytes arise from…
stem cells in bone marrow, mature there and then migrate to peripheral lymphoid tissue (follicles of LNs, white pulp of spleen).
When Ag is encountered, B cells will…
differentiate into plasma cells that produce Abs and memory cells.
B cells can function as…
an APC via MHC II.
T lymphocytes originate from…
stem cells in the bone marrow but mature in the thymus.
The costimulatory signal necessary for T-cell activation is…
CD28.
The primary target of HIV is…
CD4+ helper T cells.
Plasma cell appearance
eccentric nucleus clock-face chromatin abundant RER well-developed Golgi apparatus
Universal recipient of RBCs
AB blood group
Universal donor of plasma
AB blood group
Universal donor of RBCs
O blood group
Universal recipient of plasma
O blood group
Rh- mothers who are exposed to fetal Rh+ blood (oftenduring delivery) may make…
anti-Rh IgG. In subsequent pregnancies, anti-Rh IgG crosses the placenta causing hemolytic disease of the newborn (erythroblastosis fetalis).
Rho(D) immune globulin is given for…
mothers during every pregnancy to prevent intial sensitizaiton of Rh- mother to Rh antigen.
Warfarin acts by…
inhibiting the enzyme vitamin K epoxide reductase to prevent maturation of coagulation factors.
Neonates lack enteric bacteria which produce…
vitamin K.
Vitamin K deficiency leads to…
decreasd synthesis of factors II, VII, IX, X, protein C and S.
vWF carries/protects…
factor VIII.
Antithrombin inhibits…
activated forms of factors II, VII, IX, X, XI, XII.
Heparin enhances…
the activity of antithrombin.
Principal targets of antithrombin
thrombin and factor Xa
Factor V Leiden mutation produces…
a factor V resistant to inhibition by activated protein C.
tPA is used clinically as…
a thrombolytic. It converts plasminogen to plasmin which then causes fibrinolysis.
A normal platelet aggregation response is not seen in…
von Willebrand disease.
Acute phase reactants in plasma (fibrinogen) can cause…
RBC aggregation, thereby increasing RBC sedimentation rate.
Increased ESR (erythrocyte sedimentation rate) is seen in…
infxns autoimmune diseases malignant neoplasms GI disease (UC) pregnancy
Decreased ESR is seen in…
polycythemia sickle cell anemia CHF microcytosis hypofibrinogenemia
Acanthocyte (spur cell)
-liver disease -abetalipoproteinemia (states of cholesterol dysregulation)
Basophilic stippling
-anemia of chronic disease -alcohol abuse -lead poisoning -thalassemias
Bite cell
G6PD deficiency
Elliptocyte
Hereditary elliptocytosis
Macro-ovalocyte
megaloblastic anemia (also hypersegmented PMNs) marrow failure
Ringed sideroblast
sideroblastic anemia (excess iron in mitochondria)
Schistocyte/helmet cell
DIC TTP/HUS traumatic hemolysis (mechanical heart valve prosthesis)
Spherocyte
hereditary spherocytosis autoimmune hemolysis
Teradrop cell
bone marrow infiltration (myelofibrosis) *RBCs shed a tear bc they have been forced out of their home in the bone marrow.
Target cells
HbC disease Asplenia Liver disease Thalassemia
Heinz bodies are seen in…
G6PD deficiency; Heinz body-like inclusions are seen in alpha-thalassemia.
Heinz bodies cause….
oxidation of Hb sulfhydryl groups leading to denatured Hb precipitation and phagocytic damage to the RBC membrane forming bite cells.
Heinz bodies are visualized with…
special stains such as crystal violet.
Howell-Jolly bodies are seen in pts with…
functionl hyposplenia or asplenia.
Howell-Jolly bodies are…
basophilic nuclear remnants found in RBCs. They are normally removed from RBCs by splenic macrophages.
Iron deficiency can be caused by…
chronic bleeding, malnutrition/absorption disorders, pregnancy
Iron deficiency decreases…
the final step in heme synthesis leading to a microcytic, hypochromic anemia.
Findings in Iron Deficiency Anemia
-decreased iron -increased TIBC -decreased ferritin -fatigue -conjunctival pallor
Iron Deficiency Anemia may manifest as…
Plummer-Vinson syndrome which is a triad of: 1. iron deficiency anemia 2. esophageal webs 3. atrophic glossitis
alpha-thalassemia has a defect in…
alpha-globin gene (deletions) leading to decreased synthesis.
cis alpha-thalassemia deletion is prevalent in…
Asian populations. The trans deletion is prevalent in African populations.
alpha-thalassemia (4 allele deletion):
-no alpha-globin -excess gamma globin forms gamma4 (Hb Barts) -incompatible with life (hydrops fetalis)
alpha-thalassemia (3 allele deletion):
-HbH diseae -very little alpha globin -excess beta-globin forms beta4 (HbH)
alpha-thalassemia (1-2 allele deletion):
no clinically significant anemia
Beta-thalassemia is…
a microcytic, hypochrmoic anemia due to point mutations in splice sites and promoter sites leading to decreased beta-globin synthesis; prevalent in mediterranean populations
Beta-thalassemia minor (heterozygote) features
-beta chain underproduced -usually asymptomatic -diagnosis confirmed by increased HbA2 (> 3.5%) on electrophoresis
Beta-thalassemia major (homozygote) features
-beta chain absent (severe anemia requiring blood transfusion) -marrow expansion (“crew cut” on skull x-ray) leading to skeletal deformities (chipmunk facies) -extramedullary hematopoiesis (hepatosplenomegaly)
Beta-thalassemia major pts are at increased risk for…
parvovirus B-19 induced aplastic crisis.
Beta-thalassemia major has increased…
HbF which is protective for the 1st 6 months of life (no symptoms).
HbS/beta-thalassemia heterozygote
mild/moderate sickle cell depending on amount of beta-globin production
Lead inhibits…
ferrochelatase and ALA dehydratase leading to decreased heme synthesis and increased RBC protoprophyrin;
Lead also inhibits…
rRNA degradation causing RBCs to retain aggregates of rRNA (basophilic stippling).
High risk of lead poisoning in…
old houses with chipped paint.
Lead poisoning findings
-lead lines on gingivae and long bones -encephalopathy -erythocyte basophilic stippling -abdominal colic -sideroblastic anemia -wrist and foot drop
1st line treatment for lead poisoning is…
Dimercaprol and EDTA.
In kids with lead poisoning, treatment is…
Succimer for chelation. (It SUCks to be a kid who eats lead.)
Sideroblastic Anemia is due to…
a defect in heme synthesis.
Hereditary sideroblastic anemia
X-linked defect in delta-ALA synthase gene
Causes of sideroblastic anemia
-genetic -acquired -alcohol -lead -vitamin B6 deficiency -copper deficiency -isoniazid
Sideroblastic Anemia presents with
-increased iron -normal TIBC -increased ferriting -ringed sideroblasts (w/ iron-laden mitochondria)
Treatment for sideroblastic anemia
pyridoxine (B6 - cofactor for delta-ALA synthase)
Megaloblastic anemia is due to…
impaired DNA synthesis. This causes the maturation of the nucleus of precursor cells in bone marrow to be delayed relative to the maturation of the cytoplasm. This causes abnormal cell division leading to pancytopenia.
3 types of megaloblastic anemia
-folate deficiency -B12 deficiency -orotic aciduria
Causes of folate deficiency megaloblastic anemia
-malnutrition (alcoholics) -malabsorption -anifolates (methotrexate, trimethoprim, phenytoin) -increased requirement (hemolytic anemia, pregnancy)
Findings of Folate deficiency
-hypersegmented neutrophils -glossitis -decreased folate -increased homocysteine but normal methylmalonic acid -NO neuro symptoms (distinguishes from B12 deficiency)
Causes of B12 deficiency anemia
-insufficient intake (vegans) -malabsorption -pernicious anemia -Diphyllobothrium latum -proton pump inhibitors
Findings of B12 Deficiency
-hypersegmented neutrophils -glossitis -decreased B12 -increased homocysteine -increased methylmalonic acid -neuro symptoms
Neurologic symptoms of B12 deficiency are due to..
subacute combined degeneration due to involvement of B12 in fatty acid pathways and myelin synthesis.
Neuro symptoms of B12 Deficiency
- peripheral neuropathy w/ sensorimotor dysfunction 2. dorsal columns (vibration/proprioception) 3. lateral corticospinal (spasticity) 4. dementia
Orotic aciduria is due to…
the inability to convert orotic acid to UMP because of a defect in UMP synthase.
Orotic aciduria presents in…
children as megalobastic anemia that cannot be cured by folate or B12 with FTT.
Orotic aciduria does not have…
hyperammonemia (which distinguishes it from ornithine transcarbamylase deficiency).
Findings of Orotic Aciduria
-hypersegmented neutrophils -glossitis -orotic acid in urine
Treatment for Orotic Aciduria
uridine monophosphate to bypass the mutated enzyme
Causes of nonmegaloblatic, macrocytic anemia
-liver disease -alcoholism -reticulocytosis -drugs (5-FU, zidovudine, hydroxyurea)
Findings of nonmegaloblastic, macrocytic anemias
macrocytosis bone marrow suppression